OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Briggs & Stratton Engines Masport 460 engine swap

Hey Guys,
I have an old Masport 460 which I really like to mow with. The big propeller style blade cuts well. The only problem is, the motor is blowing lots of blue smoke and using lots of oil.

I have decided to swap the engine out with another 3.5 hp briggs.

My question is quite a simple one, and I'm sure it will be an easy answer for someone.

Any tips on getting the blade adaptor off the bottom of the crankshaft to swap onto the other motor? I'm pretty sure it just slots on and has a keyway to stop it moving. It's pretty tight and I'm out of ideas.




Any suggestions greatly appreciated.

Cheers
Sam

If it is just tight on the shaft (probably rusted on, as well as deliberately made tight) there is a fairly standard process. First, you put Penetrene on both sides of the boss where it goes over the shaft, and leave it for a day or more (you may need to wet it again occasionally). If you insist on using WD40, make that a few days, or a week or two, whatever it takes. Then get a bolt a bit longer than the original one and screw it into the end of the crankshaft, so when it bottoms in the thread in the crankshaft, its head is about half an inch away from the crankshaft. Center-drill a small recess in the center of the head of that bolt, to locate the pointy end of the screw on a gear puller. Then you can use a gear puller across the back edge of the boss (not across the flat plate on the bottom of the boss, that isn't nearly strong enough). Apply a considerable amount of tension on the puller, then tap the head-end of the puller's screw once with a hammer, tighten up the puller some more, tap the head of its screw again, and proceed that way until it starts to get easier. Then you can partly unscrew the bolt in the end of the crankshaft, and pull it the rest of the way off.

A 4" or 6" two leg puller is the only way you will get that off.


You need a bolt thats longer than the old one by the length of the height of the boss.
As Grumpy said, you need the puller to hook on the top of the boss, not the plate thats welded to the bottom of it.



The motor you get as a replacement, theres 3 shaft lengths that are comonly used, the one you need is the middle one. Its about 62mm or something. If you can only get the longer 82mm you could space the motor up 20mm with three spacers.


Tipping the mower over that way, do you do that often??? That will make it smoke.

Thanks for the tips. I went and borrowed a puller off a mate, worked a treat on one shaft, the other is still really tight. Gave it a bit more spray and left it for a while (don't have any penetrene but should go get some).

I checked the shaft lengths, they are the same luckily.

Never usually tip the motor over like that, only so I could get access. I have drained the oil out and am throwing that motor away anyway.

Hopefully I can get the other boss off. I had it done up pretty tight and it didn't move at all...

Thanks for the help.
Cheers
Sam

How tight???


I put a 9/16 spanner on the head of the bolt that i put into the crank. Set it on the hex of the bolt and against a leg of the puller so the bolt does not wind when you do the puller up.
Then an 18" or so tyre lever through the puller and onto the table/floor. Then a 12" shifter and start winding. Ive never had one that didnt move before it came time to really start grunting into it.


You can cut them through with the grinder and split the last bit with a cold chisel over an anvil.